<!DOCTYPE html>
<style id="sheet">
@keyframes test { to { } }
</style>
<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<script>
test(() => {
  var keyframeRule = document.styleSheets[0].cssRules[0].cssRules[0];
  sheet.remove();
  gc();
  keyframeRule.style.left = '0px';
}, "Don't crash when mutating @keyframes rules that have been detached from the document.");
</script>
